What is the use of the __get () and __set functions in PHP classes?

When you try to get an unreachable variable, the class automatically calls __get.

Similarly, when you try to set an unreachable variable, the class automatically calls __set. In the Web site, these two are not functions that are not intended to be used. For example: Class Test { private $a = 1; private $b = 2; Public $c = 3;   Public function __get ($vname)     { return "You can not get";     }   Public function __set ($vname, $value)     { echo "You can not set";     } }   $t = new Test; Echo $t->a;//here trying to print out a private variable $t->b=3;//Here is trying to set the private variable If you want to operate directly on a private variable, you can't do it, of course. so at the time of reading, call __get (), output "You can not get"; at the time of setting, call __set (), output "You can not set". By the way, the __get () and __set () functions are set to public, otherwise they will be warning. The parameters of the __get () and __set () functions are 1 and 2, respectively, and cannot be omitted, regardless of whether the function is useless. By modifying the statements inside the __get () and __set () functions, you can implement a private variable that calls the class externally. For example: private __get ($vname) { return $this $vname; }If the value of $vname is a, then the correct value is returned. __set () is also the same.

Public Function __set ($vname, $value)
{
$this $vname = $value;
}

What is the use of the __get () and __set functions in PHP classes?